A soak in the tub is always pleasurable, but sex in the tub is twice as nice.
1. Set the scene.
Think dim lighting, lit candles, and a sexy soundtrack. Maybe even a glass of wine if you're up for it. Be sure to have on hand anything and everything you might need once you're in. In this case, I'd set aside waterproof lube since H2O washes away any natural lubrication.
2. Find the perfect temp.
Not too hot, not too cold, and remember: the longer you're in there, the cooler the water becomes. Start off with a bit warmer than you want it, and it will be ideal by the time you start getting it on.
3. And the right water level.
Too much water in this case will make for splashing and slipping. Ideally—and if you don't have waterproof lube on hand—you'll want it low enough that you can maneuver in and out of it. It's always best to have options, and you can always add more water later, or drain it if need be.
4. Assume your position.
Here are two carnal positions that work well in this scenario: One is where your man lies back, and you straddle him while facing away from him. Then, place your hands on the bottom of the tub to steady yourself and ride him with his hands holding on to your hips. If that's uncomfortable for your knees, you can try sitting on his lap and wrapping your legs around his body.
5. Scrub each other down.
Once you've had your fun, it's time for a lil rub-a-dub-dub. I recommend not adding bubbles until this point because it's probably not best for your netherbits. There's very few things I enjoy more than washing each other's bodies, and, better yet, washing one another's hair. I find it incredibly intimate and romantic. It's almost better than cuddling!
6. Towel off.
The unfortunate part about having sex in the bathtub is that it has to end. At some point you'll both be prunes. But guess what? Drying each other off can be pretty sweet too, and if you're still up for some one-on-one, the bed isn't far away!